This (printf of an undefined value) is a good example. Thank you! Most of the time, MemorySanitizer is used with instrumented libc++ and sometimes even libc, w

This (printf of an undefined value) is a good example. Thank you! Most of the time, MemorySanitizer is used with instrumented libc++ and sometimes even libc, which allows to catch most of the cases (including printf), as the data ends up in conditional branches. Still, your point is very valid.